When extrusion and/or calendering are used in industry to produce products from plasticized thermoplastics, in particular flexible PVC, the PVC powder is treated with the plasticizer and, if desired, with other additives in a combined heating/cooling mixer system to give what is known as a dry blend, or at a higher temperature to give an agglomerated material. This dry blend or agglomerated material may then be processed by conventional extrusion to give the desired products. Preparation of a dry blend usually takes place at a temperature of from about 50 to 100xc2x0 C., and during this all of the plasticizer penetrates into the individual PVC grains, giving a dry, free-flowing mixture.
The preparation of a dry blend or agglomerate required for extruding plasticized PVC almost always takes place in batches, and considerably more energy, time and technical equipment are necessitated by this additional step.
The object of the present invention is therefore to provide a simplified process for producing products made from plasticized thermoplastics, in particular flexible PVC, by means of an extruder.